There is a single "clunk" sound between acceleration and deceleration and there is a very soft "humming" sound that i can hear while parked with my rpm's up just a bit. (I do not have a tach, so best I can say is it happens when i push the gas pedal just enough to raise rpm's, barely above idle speed). Lastly, at 25 to 35 or so, the ride is smooth, when i get up in speed around 55 or 65 there becomes a bit of a vibration... this will go away if I am coasting down a hill (there is about a 6 mile stretch of steep grade i coast down 5 times a week during commute) the ride is quiet and smooth while coasting.

The humming/whirring sound comes from engine compartment, the clunk noise sounds like it is coming from center of truck, below center console.

edit... and while im at it, i just remembered my alternator guage (ammeter) shows low charging (battery light on) at idle, and then overcharging at normal driving speed... i have to turn lights and fan on full blast to bring down to about 13 on the meter.

whirring sound could be vac pump, balancer torque convertor or the balancer pulley.

Clunk vibration sounds like a u-joint or steady bearing if you have 2 piece driveshaft. The tranny/tcase shouldn't really make a vibration that goes away much without load. I did have one that I though the Tcase was going out by the noise and it turned out to be a bad mount. When you finish a highway drive, crawl under and feel all the u-joints, a warm one will tell you its burning out.

I will check the joints after a long drive. I commute 100 miles a day, so that shouldnt be a problem. haha. Any thoughts on the alternator? Its only a couple months old... I am going to check the belt tension, hope that tightening it will solve the problem. haha. On another note, ive had a turbi and exhaust manifold in the back for at least two months now, havent had the chance or probably gutts to start that project!

yes, alternator bearing can make a noise too. if you don't have a mechanics stethoscope, put a long screwdriver on the save accessories to do so and other end of ear and see if you can zone in on noise.

Hi guys. Been a while. Ive checked torque converter no loose bolts. No exhaust rattles, no front motor rattles, not coming from drive shaft components. I noticed that if the suburban is in park, 1, 2, 3, etc.. rattle rattle rattle... if in neutral no rattle. Sounds like the noise comes from very near to front of transmission. Is there a transmission pump or anything to be rattling around in there? It shifts out fine. Again rattles only in all gears and park at idle... neutral no rattle... feather the gas pedal (haha feather it) and the rattle disappears.... not sure if it dissapears in park though, havent checked that.

Ok more info! So if the truck is in park and i push on it from the back (just using my body to push it) the more pressure I can put on it, the louder the rattle gets! Its practically non existant if there is no "bind" on the tranny or whatever. Any ideas?

Couldn't tell from the posts if you found the clunk under load or not, if not, you might want to check the pinion bearings or the leaf spring ubolts. My k1500 had a clunk when the clutch was released in first and I traced it to a loose ubolt. It was allowing the axle to move back and forth when under load (scary when I thought about it).

__________________
95' GMC K2500 Suburban 6.5 TD OPS relay mod, FFM eliminated w/ NAPA 12 micron filter/water separator plumbed upstream of LP, fuel pressure gauge w/ remote mount, Boost gauge, PMD mounted behind grille w/ custom extension, and more goodies to come
85' Chevy M1009 Blazer, 6.2 NA stock from military but hey, I just got it and haven't had time to play with this and my welder yet.
92' Chevy K1500, 350 TBI gasser (until it dies and a 6.2 or mech 6.5 takes it's place) Factory NV4500, 4.10 sets with auburn locker out back and a soon to come Dana 60 SAS
91' Mitsu Montero awaiting 4BT transplant UPDATE: gone to the big junkyard in the sky as a little square after my boys who currently have trouble sitting, shot out all the windows and replacing them would have cost more than I paid for the truck to begin with.
80's ish Belarus tractor that just wont die no matter how hard people try.

You mentioned tightening flex plate bolts, but have you pulled the trans back to inspect the flexplate for cracks? I had that happen a couple times and at first it was annoying rattles and then got worse. Whenever I hear rattles that is my first thought (I never want to change another one! lol ). but im paranoid about flexplates...

Thanjs for the advice Jr. I woukd never want to remove a tranny... well not on anything I needed to drive daily! Haha. I had to do it in a jeep a couple times... ring gear kept going out... pull a tranny and x-fer case to fix a ring gear.. and tgen install the starter wrong... twice! Anyways... today I jad themost expensive clamp repair, but the cheapest transmission repair! I was headedto work.. tons of gray smoke, at first I thought it was fog, but then I realized the cars were all eapidly changing lanes behind me... I pulled over to find tranny fluid dripping no pouring out into the ground... naturally the F word came to mind... long story short... im tired of working on this thing, sobi slide underneath, bit of bailing wire on the at fluid coolant hose, take it easy to a mechanic, he says 20.00 to puts a new wormgear screw type clamp onto my hose, naturally the F'bomb comes to mind again.. so I ask him to jusg listen to the rattle and ill get my own clamp for .75 at walmart... he listens to the rattle, finds a loose support bar... 5 minutes later, 20.00 bucks broker, im back on the road rattle free! Best 20.00 ive ever spent! Lol

Register Now

In order to be able to post messages on the Diesel Place : Chevrolet and GMC Diesel Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

PLEASE READ! You must check your email inbox for the confirmation link to complete registration. Please check your spam box if you do not see the email in your inbox.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Log-in

User Name

SAVE

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.

AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.